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Discussion Starter #1
Looking for opinions on going back to original cast iron manifolds on my non- Ram Air 1971 GTO? For anyone with experience, what are the pros and cons of original cast exhaust versus after market headers. I am having the engine pulled and painted and will be replacing the current rusty 15 yr old Hedman headers. I would like something that will hold up cosmetically and perform well.

Forgive if this is an overdone subject.

Thanks in advance.

Dan
 

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Looking for opinions on going back to original cast iron manifolds on my non- Ram Air 1971 GTO? For anyone with experience, what are the pros and cons of original cast exhaust versus after market headers. I am having the engine pulled and painted and will be replacing the current rusty 15 yr old Hedman headers. I would like something that will hold up cosmetically and perform well.

Forgive if this is an overdone subject.

Thanks in advance.

Dan
Hey Dan,

Well here ya go.
Pros
Fitment - These cars were not built to accommodate headers, and neither were the heads.
Clearance - Your exhaust will not be as likely to bottom out on you.
Flow - If you get the right exhaust manifolds, they will flow as well or better than most aftermarket headers.

Cons
Cost - A good set of manifolds, the desirable ones that flow well, ain't cheap.
Looks - It's harder to keep stock manifolds looking pretty under the hood.


That's all I can come up with off the top of my head. I think you have chosen wisely.
Scott
 

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Discussion Starter #3
Thanks Scott. You are echoing what the professional engine guy advised me on. He said the Hedmans that are on it were a bugger to get on.

Which are the ones that flow well and aren’t cheap ??

If I'm doing this, I might as well do it right. My goal is to have the engine compartment more or less back to stock but still have some high performance.

Dan
 

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Oh heck that's easy.
Ram Air III IV V
High Output
Super Duty

Any of those stockers are killer exhaust manifolds. Some are made re-production. But again, can get kinda spendy.
 

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You may want to try ramairrestoration (DOT) com
They have RA and HO manifolds in reproduction that are quite nice. I will probably go that route too.

Good luck.
:D
Scott
 

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Discussion Starter #6
I looked at the RAs on ramairrestoration.. Nice, and not too bad a price until you drop 199 extra for coatings! Wonder if worth it to keep it pretty.

Dan
 

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Well, just to offer a lightly different slant. While it's true that manifolds will fit better and will be more durable than any header, a good header will make more power than any manifold. If that weren't true then you'd be seeing manifolds on race cars instead of headers.

The decision to be made is whether or not you're willing to put up with the aforementioned fit, clearance, and longevity issues in order to get the most power you can get out of your engine.

Bear
 

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tell it like it is. Headers on a vintage car driven on the street through mufflers in stop and go traffic and even highway speeds, you do not get the full benefit of the header. on the track, uncorked, sure, but on the street with stock gearing and typical rpm, as shown by the car magazines is not there. along with the leaks, clearance, better to go with HO ram air cast manifolds and exhaust system to match.
 

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Tubing headers on the street are more for bragging rights than anything else. They make a little bit more horsepower uncorked and at the track, as stated, but on a full exhaust car pm the street, there is no real performance gain...not a huge one, anyway. My take is that for 99 percent of driving, cast iron's are fine. I have stock cast irons on my '67, and leaky Heddman's on my '65 that I installed when I was a 21 year old kid almost 30 years ago. For a street driven car at normal rpms, cast iron manifolds might even yield more torque.
 

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Discussion Starter #12
Great input. The more I think on it, since the engine is getting a spit shine back to stock color, I'll probably go with the gray coated round port Ram Air manifolds.
Will post a few pictures of the car in a few days when I get her. Engine restoration is a month or so away, so input like this helps me get the needed parts now.

Thanks again,

Dan
 

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Round port manifolds are only compatible with round port heads. If you have them, great. If you have normal D port heads, the HO manifolds work very well and fit just fine.
 

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I have used headers on my 69 Goat as long as I have had it, didn't have performance cast iron then. I am on my third set now. Some tips... The best time to install is when the front clip is off, or at least the inner fenders, remove the starter, oil filter adapter, the back drive linkage for autos, clutch linkage for manual. Install from underneath, and use quality gaskets. I have had good luck covering both sides of the gasket with a thin film of copper RTV. Now I got a great deal on a set of new ceramic coated headers. I used the new carbon gaskets from Percys, they look like black velvet stuck to a metal core. I also used Stage 8 locking header bolts made for big block chevy, they are longer. Haven't started the engine yet, still putting the car together.
Having said all that, I would go with RA cast iron if I wasn't already set up for headers, and had a set of coated headers fall into my lap.
 

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I went with the Ram Air manifolds because my heads were not drilled to accomodate the outside bolt holes for the headers that were already on it. Without these outside bolts it was impossible to get them to seal properly. I would have spent more to take off the heads and have them drilled that I spent on the manifolds. I also did not want to open a can or worms by taking the heads off and discovering that I needed new rockers, etc. The headers that were on the car actually warped because they could not be secured properly. I am waiting for my manifoods to be delivered and then I plan to spray them with my own $8 can of ceramic coating and bake them in the oven before I install them.
 

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Discussion Starter #17
I am definitely going with the RA manifolds. Yesterday I saw a set of the coated gray ones in a similar car. The owner said they are a breeze to keep looking brand new and definitely recommended the coated. I figured I would go ahead and spring for the coated if I am going to enter shows.

I just hope I don't lose to much of the badass sound. I'll still have the flowmaster 40s but I'll probably lose some of the port chatter.
 

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I looked at the RAs on ramairrestoration.. Nice, and not too bad a price until you drop 199 extra for coatings! Wonder if worth it to keep it pretty.

Dan
I put a set of R.A.R.E. long branch cast headers on my 64 gp and they fit and look great (paid for gray coat too). the only draw back was on top of the $900 for the man's (ship to ontario canada from cali incl.) i needed i mini starter and the oil filter extension piece. all told was about 1400 cdn. i couldn't find a set of tube headers to work on my b-body so this ended up being my solution. With flowmaster 40's they will still sound bad ass. Mine sounds awesome. My .02
 

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I bought a set of Dougs ceramic coated for my 65. Have not installed yet. Was reading in the instruction sheet that they are not recommended for initial breakin of the engine. May damage the ceramic coating??? Can anyone comment of this? Do I have to go out and buy another set of manifolds or headers for break in? I have E heads on the 455 right now. Thanks
 
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